HOLOGRAPHIC PERFECT SHUFFLE PERMUTATION ELEMENT FOR A MINIATURIZED SWITCHING NETWORK

A holographic perfect shuffle element with 80 channels for a miniaturi zed switching network is reported. An array of vertical-cavity, surfac e-emitting lasers is used as a transmitter. The whole permutation is c arried out totally in glass. The 80 channels are permuted within a rec tangle with a volume of 3 mm x 4 mm x 2 mm. Four planes of stacked vol ume holograms recorded in dichromated gelatin form this perfect shuffl e element with an angular spectrum between 7 degrees and 35 degrees. C hanges in the wavelength of the diode lasers to Delta lambda = +/- 10 nm can be compensated with this setup. The overall efficiency per chan nel lies between 40% and 60%. When Fresnel reflections and absorption are taken into account, a transmission per hologram between 78% and 90 % is achieved.